ICrpg mod/ D20system - The none binary dice system


Hello everyone, i’m hopin’ you’re good. ^^

As everyone knows … i love Dungeon World and one stuff i really enjoy as a gamemaster during a play session of DW is the three results dice system ( 6- ; 7 - 9 ; 10+). It allows so much cool improv’. ^^

But I play also a lot of Pathfinder, Dnd, ICrpg, D20 system and i wanted to add that feature into those games.

So i did that…

On a d20 roll:

  • Nat 1 : Big fail, heavy consequence for the player (GM has to decide what it is)

  • Under the challenge rating *« a Fail forward » or the player what he wants but he has to pay a big price for it. *The GM get to make a move if he thinks it is appropriate.


  * Between the challenge rating and challenge rating + 4: *Success but at a low cost. The GM has to decide what. **The GM get to make a move if he thinks it is appropriate.*


  * Challenge rating +5 : *Success and the player has to do what he
    initially decided to, with no cost.*
  • Nat 20: The hero does an extraordinary action.

**The DM moves are from the Dungeon World rules. ( http://www.dungeonworldsrd.com/gamemastering/)

I also made those targets for ICrpg representing the main target and the smaller one represent the “CR + 5”.



Thank you for reading the post. The rules i made is just an attempt to adapt some rules from DW to D20system as i said and it is not tested at all so i don’t know if it will improve your D20syst gaming session (hope it does).
Soooo, let me know what you think about that little adaptation. ^^


Here’s a couple alternatives for what you want, some of them had been posted on the old Google+ forums:

Since the game already uses EASY&HARD mechanic with +/-3 steps, let’s build upon that.
Example target is 12 & the attempts below are modified rolls.

12-14 is normal success
15-17 great success
18-20 super success

9-11 is normal failure
6-8 great failure
3-5 catastrophic failure

Nat 1 and 20 are regular crits with their own effects (whatever the DM sees fit for the situation).

The good: Character skill increases the chances of getting better results as expected.
The bad: Interpretation of the attempt is slower than the plain old attempt roll.
The ugly: Success and positive results are tied together. You can’t have a success with a bad dramatic effect.

The second alternative uses two d20s; one representing the attempt itself (binary pass/fail as usual), other representing the dramatic die described above with success/failure divorced from it.

Example: You want to persuade the duke to send aid in your quest to cleanse the gerblin hideout. You roll two d20s. Your attempt succeeds but your dramatic die fails. The duke agrees to send soldiers with you but the soldiers he sent are actually loyal to the duchess, who hates your guts.

The good: Character skill increases the chances of getting better results as expected + success is independent from dramatic result i.e you can pass but still get negative results and vice versa.
The bad: Slowest method to roll and interpret. So maybe limit this to really dramatic moments.
The ugly: Did I mention slow?

Third alternative: Similar to the previous approach. Roll attempt normally (pass/fail) and in addition roll a d4 for dramatic result instead of the second d20.
1 worst negative outcome
2 negative outcome
3 positive outcome
4 most positive outcome

The good: Simplest and fastest dramatic resolution.
The bad: Maybe too simple?
The ugly: Dramatic result is random; doesn’t take character skill into account at all.

I am thinking of introducing more dice to the game

I’ve been revisiting DW and pondering how I might incorporate a partial success into ICRPG. Here’s an idea I haven’t playtested yet:

Roll as usual. On any fail besides a natural 1, the player may choose to succeed at a cost. The cost is the same as a critical failure, and it is resolved first. Random fumble tables might be helpful here.

I speculate this would slow gameplay slightly as players decide whether or not to take the cost. You could count down from five to mitigate this. Depending on the type of fumble, there’s a chance the PC might be incapacitated before they get their success. So it’s a tough choice to make.


If you want to emulate the DW dice system to ICRPG, just drop the d20 from ICRPG and adopt the 2d6 like DW. Adjust your TARGETS down a couple points and the difference between the two die types is close enough that it won’t matter much.

Trust me… It’s the easiest way without changing all the math, and you get to keep the “fail forward” game concept of Dungeon World.


Wouldn’t it be easier to pick up Kult’s 2d10? Way closer match and also has the partial sucesses…


I don’t know about easier, but it is a simple alternative. The 2d6 is already part of DW so the transitition to ICRPG using 2d6 would be a no brainer… as for the 2d20 system its not a DW mechanic.

But as we always say, It’s your game, play it your way… I know I do!


(It’s cause DW is 2d6, not 3d6…)


sorry I meant 2d6… I have corrected my mistake in the comments prior.


I too like the DW “Fail Forward” and Fate “Success at a Cost” option, but I just don’t want all that extra math.

So here’s what I sometimes allow: If the PC misses the target by 1 (example: gets a modified 11 on a Target 12) the GM may offer the chance to convert the failure to a success by adding a GM determined additional cost.

Sometimes I tell the cost before they decide, sometimes not. Depends on the situation.

This is a whole lot less brain-required to keep track of. And keeps the fast action moving at the table.

I also use single roll Blunders for Nat 1, so this feels like a more natural fit with the pulpy tone most of my games have.


I saw this post a while ago and I’m also a huge fan of DW, so I’ve been thinking about tweaking a little the original idea @JulesWalther posted and finally I came with this:

This is fully-based on @ChrisWolfie table tents (Give him credit) and basically takes the TN and splits it in two TNs, one 2 units higher and other 2 units lower. (The image above comes from TN 12).
The EASY and HARD modifiers still apply so some actions can roll for 7-11 (EASY) or for 13-17 (HARD) instead of 10-14.

This way we (the GMs) can still rachet up or down the difficulty in two ways, temporary (EASY/HARD) or permanently (changing the TNs) as proposed at the beginning, but I also played a little with the critical rolls.
I don’t like the idea of having a 10% of the rolls being either a crit or a blunder (5% each one) typical of d20 systems. So I took the crit and incorporate it as a new level of success. You roll, add the stat and loot that applies
and if you meet or beat the crit TN, you can roll ULTIMATE or gain whatever reward the GM decides.

This way, this system create situations where only some players will be able to crit (the specialists on that task/stat). So that epic boss with a high room TN won’t insta-die cause a very lucky roll from the floppiest PC.

For blunders I took a different approach (because if you add stats, some players will have no possibility to blunder… and that’s something we can’t accept… MUAHAHAHA!) If someone rolls a nat-1, then roll for a blunder (like vanilla ICRPG) but now they need to meet or beat the lower TN (that’s why the 1 appears in the same card as the lower TN) adding the loot and stat mods like in the previous roll (EASY and HARD mods still applies if any) this way the probability of blunder also rachet with the general TN and more specialised PCs will have a slightly lower chance of fatal failure than their mates.

In this link you’ll find all the images and a pdf version of the tents and also a very confusing GIMP file with all the images.

Please give me your comments, I’ll appreciate them.